Amazon S3 Transfer Acceleration: Complete Guide

What You Should Know Before Enabling S3 Transfer Acceleration

I’ve been working with S3 Transfer Acceleration for a while now, and I want to share what actually matters when deciding whether to use it.

S3 Transfer Acceleration can speed up how fast you move large files to and from Amazon S3, particularly when you’re dealing with long distances or spotty internet connections. Media companies, research institutions, and government agencies often find this useful since they move large amounts of data routinely.

To get started, you enable Transfer Acceleration on your S3 bucket. Once it’s on, data automatically routes through Amazon’s optimized network paths. You manage this through the AWS Console, CLI, or SDKs. One thing worth mentioning: you can also use S3 prefixes to speed up downloads.

How CloudFront Edge Locations Work

CloudFront maintains a network of servers positioned around the world. These edge locations cache and deliver content like videos, images, and web pages. When someone requests content, CloudFront routes them to the nearest edge location, which cuts down on latency.

The exact number of edge locations changes as AWS expands, but they cover many countries across multiple continents. These locations connect to the AWS backbone network, which provides high bandwidth and low latency for content delivery.

Beyond content delivery, CloudFront edge locations also support S3 Transfer Acceleration, Lambda@Edge, and AWS WAF. All these services benefit from CloudFront’s global presence.

You can test the speed difference between regular and accelerated transfers here.

The AWS Backbone

The AWS backbone is the global network connecting AWS data centers, availability zones, and edge locations. It’s a high-bandwidth, low-latency infrastructure that forms the foundation for AWS services.

The backbone uses fiber-optic cables spanning multiple continents, connecting data centers, edge locations, and points of presence. AWS employs advanced networking technologies like optical networking, software-defined networking, and network function virtualization to optimize performance and reliability.

Many AWS services rely on this backbone infrastructure, including S3, EC2, RDS, Aurora, and Redshift. It provides the network connectivity that enables these services to deliver the performance and availability users expect.

How S3 Transfer Acceleration Actually Works

Here’s what happens when you use Transfer Acceleration:

1. You initiate a transfer to or from an S3 bucket
2. Transfer Acceleration must be enabled on that bucket (one-time setup)
3. AWS selects the optimal CloudFront edge location based on your location, the bucket’s region, and current network conditions
4. Your data goes to that edge location
5. Data travels over AWS’s optimized network path between the edge location and your S3 bucket
6. For uploads, data arrives at S3. For downloads, data flows back through the same optimized path

In short, Transfer Acceleration routes your traffic through CloudFront’s edge locations and across the AWS backbone rather than taking the public internet route.

You can also use S3 prefixes to improve download performance.

Cost

Transfer Acceleration pricing adds to your standard S3 storage and request costs. You pay for accelerated transfers based on how much data you move and where it’s going.

Transfer Acceleration is supported in these regions: US East (N. Virginia), US East (Ohio), US West (N. California), US West (Oregon), Canada (Central), Europe (Frankfurt), Europe (Ireland), Europe (London), Europe (Paris), Asia Pacific (Tokyo), Asia Pacific (Seoul), Asia Pacific (Mumbai), Asia Pacific (Singapore), Asia Pacific (Sydney), and South America (São Paulo).

For current pricing, check the AWS S3 pricing page since these rates change.

A few things to keep in mind:

• Transfer Acceleration adds charges on top of regular S3 data transfer costs
• The feature only works with virtual-hosted style requests
• Your bucket name must be DNS-compliant and cannot contain periods
• After enabling, it takes up to 20 minutes before you see speed improvements
• There’s a minimum charge per gigabyte transferred

Consider whether the speed improvement justifies the extra cost for your use case. Sometimes regular S3 transfers make more sense, especially for shorter distances or smaller files.

Requirements

To use Transfer Acceleration, you need:

• An AWS account
• An S3 bucket in a supported region
• A supported client (AWS CLI, AWS SDKs, or S3-compatible clients)
• Transfer Acceleration enabled on your bucket
• Virtual-hosted style requests (not path-style)

For IAM permissions, you’ll need s3:PutAccelerateConfiguration to enable or disable the feature, and s3:GetAccelerateConfiguration to check its status.

Using Transfer Acceleration with Direct Connect

You can combine Transfer Acceleration with AWS Direct Connect. Direct Connect provides a dedicated connection between your on-premises setup and AWS, which gives you more consistent performance than internet-based connections.

To use both together, you set up a Direct Connect gateway in the same region as your S3 bucket, then use Transfer Acceleration to route traffic through CloudFront’s edge locations before it goes over your Direct Connect link.

This combination works well for large file transfers, media workflows, backup and disaster recovery, and big data analytics where you need better latency, security, and bandwidth than the public internet provides.

Keep in mind that you’ll be charged for both Direct Connect data transfer and Transfer Acceleration usage.

Do You Need Cross-Region Replication?

No, you don’t need cross-region replication to use Transfer Acceleration. These are separate features.

Cross-region replication automatically copies objects between buckets in different regions. It’s useful for durability, recovery time objectives, and data residency requirements.

Transfer Acceleration uses CloudFront edge locations to speed up transfers to and from your bucket. It doesn’t replicate data.

You can use both features together if you need both cross-region data copying and faster transfer speeds, but they’re independent of each other.

Quiz Time

Amazon S3 Transfer Acceleration - Questions

What’s the difference between S3 Transfer Acceleration and direct upload?

Transfer Acceleration routes your data through CloudFront edge locations. Direct upload sends data straight to S3 over the public internet. They’re different approaches to the same problem.

How does Transfer Acceleration compare to AWS Snowball?

Snowball uses physical devices to transfer data. You ship a device to AWS, they load your data, and ship it back. Transfer Acceleration works entirely in the cloud, routing traffic through CloudFront.

What’s the maximum file size?

There’s no maximum file size limit for Transfer Acceleration.

What’s a disadvantage of using Transfer Acceleration?

The main downside is higher transfer costs compared to standard S3 data transfer. You’re paying for the accelerated routing.

How does Transfer Acceleration improve speeds over long distances?

It routes traffic through CloudFront’s globally distributed edge locations, which reduces latency by taking more direct routes across the AWS backbone.

What’s required to use Transfer Acceleration?

You need an AWS account and a supported S3 region. That’s the baseline. You don’t need cross-region replication or special storage classes.

Is Transfer Acceleration faster when uploading from the same region?

Uploading from within the same region can be faster because there’s less distance to cover, but Transfer Acceleration helps most when crossing continents or dealing with poor internet connectivity.

How is data protected during transfer?

Data is encrypted in transit using SSL/TLS, the same security used for standard S3 transfers.

Can you transfer data to and from on-premises storage?

Yes, Transfer Acceleration can reach on-premises storage solutions as long as you have internet connectivity to reach CloudFront edge locations.

How does Transfer Acceleration handle network congestion?

It dynamically adjusts the TCP window size to maximize throughput and uses CloudFront’s routing to bypass congested paths where possible.

What about large files?

Transfer Acceleration handles large files by automatically dividing them into smaller chunks for transfer, so you don’t need to manually split anything.

Does Transfer Acceleration increase costs?

Yes, using Transfer Acceleration increases your data transfer costs compared to standard S3 transfers. The amount depends on the source and destination regions and the volume of data.

Final Thoughts

S3 Transfer Acceleration is useful when you need to move large files quickly across long distances or when your internet connection isn’t ideal. It works by routing traffic through CloudFront’s global edge locations and across the AWS backbone.

Key takeaways:

• Transfer Acceleration can speed up S3 transfers significantly for cross-continent workloads
• It works alongside Direct Connect if you need dedicated connectivity
• Cross-region replication is not required
• Costs are higher than standard transfers
• Enable it on your bucket and wait up to 20 minutes for it to take effect

I hope this helps you decide whether Transfer Acceleration makes sense for your use case.